This invention relates to an outboard jet propulsion device and more particularly to an improved lower housing construction for such a device.
Many forms of outboard drives employ jet propulsion units for propelling the watercraft through the water. Such units include a vertically extending impeller shaft that rotates within a cylindrical cavity and which draws water through a downwardly and partially forwardly facing water inlet. Generally, the construction of the outer housing is such that the cavity is defined by a cylindrical portion and the water inlet is defined by a foot shaped portion.
FIGS. 1 and 2 show in side elevation and top plan the configuration of the conventional lower unit of such jet propulsion outboard drives. As seen in these figures, the lower unit housing has a generally cylindrical portion 21 that defines the impeller cavity in which the impeller is contained. A downwardly facing water inlet 22 is defined by a foot like portion 23 and which water inlet faces somewhat in a forward direction. It will be noted that there is a discontinuity in configuration between the foot like portion 23 that defines the inlet 22 and the cylindrical portion 21. As a result, the water flow as the watercraft travels through the water will be deflected back forwardly as shown by the arrow in FIG. 1 and add to the flow resistance. As a result, this type of unit consumes more power than is desirable for efficient operation.
It is, therefore, a principal object of this invention to provide an improved lower unit arrangement for a jet propulsion outboard drive.
It is a further object of this invention to provide an improved streamlining arrangement for the lower unit of a jet propelled outboard drive.